Pressure compensator for gun perforators



Feb. 27, 1.

G. F. TURECHEK PRESSURE COMPENSATOR FOR GUN PERFORATORS Filed April 26, 1939 11v VENTOR GEORGE F 717/?50/15/1' A TTOR/VE r atented Feb. 27, 1940 PRESSURE COMPENSA'IOR FOR GUN PERFORATOES George F. 'H'urechek, Los Angcles, Calif., assignor to Lane-Wells Company, Los Angeles, Calif., a corporation of Delaware 1989, Serial No. 270,129

to the concusslve or surge pressures generated when the gun perforator is fired. The side walls, however, do have suflicient resiliency that when Application My invention relates to pressure compensators for gun perforators, that is, to devices for absorbing or minimizing the surge or concussive pressures generated in a well-bore when a gun perforator is discharged under liquid.

Among the objects of my invention are:

First, to provide a pressure compensator for gun perforators which is fully operative to compensate for the volume of liquid that must be displaced in order that a'bullet may issue from the gun perforator, whether the gun perforator is submerged in the well liquids only a short distance or at a great depth;

Second, to provide a device of this character which may be attached to any type of gun perforator, such as those shown in Patents Nos. 2,048,451 and 2,062,974;

Third, to provide a device of this character which may be made relatively compact and which forms a nose or guiding element for the perforator, to facilitate movement thereof through the well; and

Fourth, to provide a device of this character which is particularly simple and economical of construction, and capable of repeated use over long periods of time without danger of deterioration or injury.

With the above and other objects in view, as will appear hereinafter, reference is directed to the accompanying drawing, in which:

Figure 1 is an elevational view of a gun perforator positioned within a well casing with my compensator shown at the lower end thereof;

Figure 2 is a fragmentary elevational view of the gun perforator and compensator taken at right angles to Figure 1; and

Figure 3 is an enlarged transverse sectional v'ew through the compensator.

My pressure compensator comprises a fitting i which is adapted to screw into the lower end of a conventional gun perforator body A. The fitting is tapered on two sides so that its cross section changes from a circular form to a substantially elliptical form, two sides however beng flat. A pressure responsive tube 2 is welded to the fitting I, as indicated by 3. The tube comprises two flat sides 3 connected by curved edges 5. The lower end of the pressure responsive tube 2 is suitably welded, as indicated by 5, to a nose piece I so that the interior of the pressure tube 2 is hermetically sealed.

The tube 2 of my pressure compensator is made sufliciently thick so that its walls or sides 6 will not collapse when subjected to the hydrotatic pressure encountered in the well-bore, or

pressure surges occur the side walls 5 yield inwardly, as indicated by dotted lines in Figure 3. 5 The size of the pressure compensating tube 2 is sufiicient to provide an aggregate volume between the solid and dotted line position indicated in Figure 3, to fully compensate for the volume of the bullet B discharged from the gun perforator. Actually it is preferred that the amount of compensation possible with the pressure responsive tube 2 exceeds the volume of the bullet by several times.

The function of the pressure compensator is exceedingly important, for without some means of compensation a volume of liquid equal to the volume of the bullet must be displaced from the point at which the bullet discharges to the top of the liquid column. When the gun is submerged to a depth of several thousand feet (and in this regard, gun perforators have been fired at depths in which the submergence in liquid was greater than 12,000 feet), it follows that there is a tremendous amount of inertia which must be overcome to displace the liquid. As a result, the explosive energy tends to dissipate itself in heat rather than in imparting velocity to the bullet. On the other hand, by reason of the pressure compensator, the liquid need only be displaced from the gun to the compensator, a matter of a few inches or, at best, a few feet.

Furthermore, and particularly by providing ample difierential volume between the normal and the compressed positions of the tube 2, surge pressures are held to a low value, thereby minimizing the danger of splitting the well casing, particularly if several bullets are fired simultanenovelty inherent in the invention as broadly as the prior art permits.

I claim: 1

l. The combination with a gun perforator adapted to be lowered in liquid within a well casing: a hermetically sealed chamber containing a compressible medium and including a pressure responsive diaphragm capable of withstanding the hydrostatic head of liquid in which the gun perforator is submerged and yieldable to by reason or said discharge.

surge pressures generated upon discharge of said gun periorator to accommodate liquid displaced 2. The combination with a gun pertorator adapted to be lowered in liquid-filled well-bores, of: a surge pressure compensator comprising a tube extending from the gun periorator, said tube being hermetically sealed and having pressure responsive areas adapted to yield to surge pressures generated upon discharge of said gun pertorator.

3. The combination with a gun peri'orator adapted to be lowered and discharged within liquid-filled well-bores, of: a surge pressure compensator comprising a hollow, flattened, elongated tube hermetically sealed and adapted to withstand the crushing force exerted by the hydrostatic head oi. liquid in which the gun periorator is submerged and yieldable to surge Dressures generated upon discharge of said gun.

4. The combination with a gun periorator adapted to be lowered and discharged within liquid-filled well-bores, 01: a surge pressure compensator comprising a hollow, flattened, elongated tube hermetically sealed and adapted to withstand the crushingsiorce exerted by the hydrostatic head oi liquid in which the gun periorator is submerged and yieldable to surge pressures generated upon discharge of said gun; and means for reinforcing said tube against collapse beyond its elastic limit.

5. Thecombination with a gun periorator adapted to be lowered and tired within a liquidiilled well-bore, oi: a hermetically sealed chamber having pressure-responsive areas forming diaphragms adapted to move into said chamber in response to surge pressures generated upon discharge oi said gun pertorator to accommodate the displacement of liquid during such discharge; and stop means for restraining movement 0! said diaphragms beyond their elastic limit.

GEORGE F. TURECHEK. 

